stanfordnlp/CoreNLP · warning

not added

Error message

${phraseText} not added

What it means

PhraseTable.addPhrase inserts a phrase into a trie. If after trying all insertion strategies nothing was added and the token list is empty (the phrase produced no words), a warning '<phraseText> not added' is logged. Non-empty duplicate phrases are handled separately via the oldphrase branch.

Solutions

1. Skip blank/whitespace-only lines when loading the phrase file.
2. Trim and validate phraseText before calling addPhrase.
3. Sanitize the source file so each record has a non-empty first field.

Example fix

// before
for (String line : lines) table.addPhrase(line, null, null);
// after
for (String line : lines) {
  if (line == null || line.trim().isEmpty()) continue;
  table.addPhrase(line, null, null);
}

if (phraseText == null || phraseText.trim().isEmpty()) {
  return; // nothing to add
}

static boolean isBlank(String s) { return s == null || s.trim().isEmpty(); }

When it happens

Trigger: Calling addPhrase with a phraseText that normalizes/splits to zero tokens (empty string, only delimiters/whitespace), so wordList.size()==0 and no trie node can be created.

Common situations: Loading a phrase file with blank lines or lines whose first field is empty after splitting; passing empty strings programmatically from user input.

Understand the failure class

Background: "must not be empty", "cannot be empty" — required-field validation errors across open-source libraries — this error's family across 41 libraries.

Related errors

• Annotation field cannot be null
• Attribute already defined:
• Attribute already defined
• Attribute match already defined:
• Attribute match already defined

AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/4e5d3061a38b28b1. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/ling/tokensregex/PhraseTable.java:452

                addPhrase(newMap, oldphrase, i+1);
              } else  {
                throw new RuntimeException("Unexpected class in list " + obj.getClass() + " while converting list to map");
              }
            }
            tree.put(word,newMap);
          }
        }
      } else {
        throw new RuntimeException("Unexpected class in list " + node.getClass() + " while adding word "
                + i + "(" + word + ") in phrase " + phraseText);
      }
      if (phraseAdded) {
        break;
      }
    }
    if (!phraseAdded) {
      if (wordList.size() == 0) {
        log.warn(phraseText + " not added");
      } else {
        Phrase oldphrase = (Phrase) tree.get(PHRASE_END);
        if (oldphrase != null) {
          int matchedTokenEnd = checkWordListMatch(
                  oldphrase, wordList, 0, wordList.size(), wordList.size(), true);
          if (matchedTokenEnd >= 0) {
            oldPhraseNewFormAdded = oldphrase.addForm(phraseText);
          } else {
            // create list with this phrase and other and put it here
            Phrase newphrase = new Phrase(wordList, phraseText, tag, phraseData);
            List<Phrase> list = new ArrayList<>(2);
            list.add(oldphrase);
            list.add(newphrase);
            tree.put(PHRASE_END, list);
            newPhraseAdded = true;
          }
        } else {
          Phrase newphrase = new Phrase(wordList, phraseText, tag, phraseData);

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